Many devices have been devised for the purpose of watering livestock and other animals. The main problem for automatic watering devices is to prevent such device from freezing up in the wintertime and to dependably provide fresh water to livestock. Some of these inventions merely have a reservoir of water on the top of a housing subject to ambient temperatures and then provide a heater in or adjacent to such pool of water to keep the water from freezing. Typically, float valves are provided for adding more water to this reservoir once the animal has drunk water from such reservoir. One of the problems with this kind of a watering apparatus is that it requires a substantial amount of heat energy to keep the water from freezing and is therefore quite expensive to operate. Another problem with this type of an approach is that the float valve often freezes and also requires considerable maintenance to keep it operating properly.
Another approach to the problem has been the use of nipple waterers. These waterers have a sealed and enclosed housing with valve members extending outwardly therefrom and having metal valve operators thereon such that when an animal places its mouth around and over the nipple valve, the valve will be open to run water into the animal's mouth; and, when the animal removes its mouth from around the nipple valve, the valve will automatically close. There are also considerable problems with this type of watering device. First of all, it seems to be more practical for hogs than for other types of animals such as cattle and horses mainly because the cattle and horses do not naturally learn to drink from this type of a device and because they must be positioned higher for larger animals. Another problem associated with nipple valves is that because they are on the outside of the sealed housing, they tend to freeze unless a large amount of heat is generated within the inside of the housing and transmitted from there to the metal portion of such nipple valve. This, again, is an energy wasting arrangement.
Still another approach to this problem is to have a sealed housing with a reservoir of water therein which has a cover of some sort thereon for sealing the compartment of water from ambient air. For example, U.S. Pat. No. 3,745,977 to Martin uses a float valve which can be opened by an animal in order to obtain access to the reservoir of water below it and which automatically closes when an animal is not exerting pressure upon it. Other patents such as U.S. Pat. Nos. 4,100,885 to Kapplinger and 4,395,974 to Schafer, et al., have reservoirs of water with pivoting covers thereon which require that the animal learn to lift the pivoting cover upwardly in order to gain access to the reservoir therebelow. One of the major problems with this type of a device is that not all animals will learn how to open the top of the device in order to drink from the reservoir therein.
Consequently, there is a need for an animal watering apparatus which is dependable, energy efficient, and which all animals will inherently know how to drink therefrom.